1818 Inorganic Chemistry, Vol. 18, No. 7, 1979
John D. Petersen and Frank P. Jakse Registry No. MnPSe,, 69447-58-1; FePSe,, 52226-00-3; FePS,, 42821-47-6; Nips3, 42821-48-7; MnPS,, 43000-56-2; CdPS,, 60495-79-6; ZnPS,, 56172-70-4; LiMnPSe,, 701 30-39-1; LiFePSe,, 701 30-40-4; LiFePS,, 70130-41-5; LiNiPS,, 65756-46-9; n-butyl-
number of electrical carriers but these carriers do not appear to be free but rather close to the conduction band. In NiPS3 the intercalation is more rapid and probably occurs as a two-phase phenomenon. The reduction in magnetic susceptibility as well as the large number of nonthermally activated electrons suggests the formation of a metallic intercalated phase. This argument is supported by recent N M R measurements which have observed a second phosphorus resonance peak with lithium intercalation.I2 It is interesting to compare the results obtained by chemical intercalation with those previously reported for electrochemical discharge. For those materials which show no change in electrical conductivity with chemical intercalation the electrical discharge drops rapidly. N i p s 3 which is the material that chemically reacted the most rapidly and showed the largest change in electrical and magnetic properties has also shown the most favorable discharge curves. It must be emphasized that the chemical intercalations carried out with butyllithium were certainly not under thermodynamic equilibrium conditions and therefore would not necessarily yield the same results as those experiments made electrochemically.
lithium, 109-72-8. References and Notes A. H. Thompson and M. S. Whittingham, Mater. Res. Bull., 12, 741
(1977). A. Le Mehaute, G. Ouvrard, R. Brec, and J. Rouxel, Mater. Res. Bull.,
12, 1191 (1977). W. Klingen, Dissertation, Universitat Hohenheim, Germany, 1969. M. B. Dines, Mater. Res. Bull., 10, 287, 1975. D. Murphy, F. Di Salvo, G. W. Hull, and J. Waszczak, Inorg. Chem., 15, 17 (1976). W. Klingen, G. Eulenberger, and H. Hahn, Naturwissenschaften, 55, 229 (1968). W. Klingen, G. Eulenberger, and H. Hahn, Nuturwissenschaften, 57, 88 (1970). R. Nitsche and P. Wild, Muter. Res. Bull., 5, 419 (1970). A. Lerf and R. Schollhorn, Inorg. Chem., 16, 2950 (1977). B. E. Taylor, J. Steger, and A. Wold, J . Solid Srate Chem., 7,461 (1973). B. E. Taylor, J. Steger, A. Wold, and E. Kostiner, Inorg. Chem, 13, 2719 (1974). C. Berthier, Y . Chabre, and M. Minier, Solid State Commun., 28, 327 (1978).
Contribution from the Department of Chemistry, Kansas State University, Manhattan, Kansas 66506
Quantum Yields and Product Stereochemistry for the Photochemistry of cis- and trans-Rh(en)2XCln+ JOHN D. PETERSEN* and FRANK P. JAKSE Received August 23, 1978
The photoaquation quantum yields and product stereochemistries for cis- and tram-Rh(en)2XC1"+(X = C1, NH,) are reported. All of the complexes undergo loss of chloro ligand and formation of Rh(en)2X(H20)n+in aqueous solution. Photolysis of the trans complexes results in stereoretentive products with quantum yields of 0.061 and 0.062 mol/einstein for X = C1 and NH3, respectively. For the cis complexes, the stereochemistry of the product depends on the nature of X. For X = C1, the quantum yield for chloro loss is 0.43 mol/einstein, and the product has a trans configuration. For X = NH,, chloro loss (a = 0.145 mol/einstein) results in the stereoretentive cis photoproduct. The stereochemical fate and mechanistic implications of the photolysis reactions of these Rh(II1) amine complexes will be discussed in terms of existing theory.
-
Introduction Ligand field photolysis of rhodium(II1) amine complexes in aqueous solution customarily leads to the photoaquation of one ligand from the complex2 resulting in a monoaquo complex as the photolysis product. Subsequent ligand photosubstitution reactions are not observed spectroscopically since further reaction is usually limited to aquo ligand exchanges3 Models4 have been proposed to explain the nature of the labilized ligand although some ambiguitiesSarise in the correlation of theory to experiment. Until recently, the theory on the photosubstitution reactions of rhodium(II1) amine complexes has been limited to the nature of the labilized ligand with no effort spent on the stereochemistry of the remaining metal fragment. This apparent lack of study was manifested by the seemingly stereoretentive photochemical behavior of the Rh(II1) complexes. Photolyses of pentaamminerhodium(II1) systems (eq 1 and 2) and trans-disubstituted tetraamine complexes (eq 3) have Rh(NH3)5Xn+
hu, LF
H2O
-
Rh(NH3)5X2+
H20
(2) I
hu, LF
HzO
+
trans-RhA4(H2O)Cl2+ C1-
A4 = (NHJ4,I0 (en)211 (4) or photochemical substitution reaction of Rh(II1) definitely indicate geometric isomerization around the metal center. Cis/trans rearrangements of M(II1) amine complexes are not limited to Rh(II1). Both C O ( I I I ) ' and ~ ~ ~Cr(III)I5 ~ amine complexes display stereomobility during photosubstitution reactions. Vanquickenborne and C e ~ l e m a n s ' have ~ ~ ' ~been successful recently in using a ligand field treatment to explain the stereochemical changes around selected d3 and d6 metal centers. In this work, we report the results of the ligand field photochemistry of some bis(ethy1enediamine) complexes of Rh(II1). In addition, we will use the ligand field analysis of Vanquickenborne and CeulemansI7 to discuss the stereochemistry of the photolysis products of these reactions as well
(1)
0020-1669/79 , ,/13 18-1818$01 .OO/O
trans-RhA4(H20)C12++ C1-
H20
-
cis-RhA4C12+
tr~ns-Rh(NH~)~(H~+ 0 )NH3 X~+ X = Br,8 Is
hu, LF
A4 = (NH3)4,9 cyclamg (3) led solely to pentaammine or trans-disubstituted tetraamine photolysis products. It was not until studies on the of cis-dichlorotetraaminerhodium(II1) complexes resulted in trans products (eq 4) did any thermalI2
Rh(NH3) jHz03++ X(3-n)-
X = NH,,6 P Y - X , N ~ E C R , ~ C1,8 Br,8 HZO2 hu LF
trans-RhA4C12+
0 1979 American Chemical Societv -
Inorganic Chemistry, Vol. 18, No. 7, 1979 1819
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Photochemistry of cis- and tr~ns-Rh(en)~XCl"+
hmax,
compd
Emax,
nm
M-lcm-'
trans-[Rh(en),Cl,] NO,
406 286
trans-[ Rh(en),(NH,)Cl](NO,),
342 275
83 (75") 134 (130") 95" 120"
352 295
203b 20Sb
342 276
150" 195"
cis-[Rh(en),Cl,]ClO,
-
bands (derived from 'T1 'Al and 'T2 IAl in the octahedral point group). Irradiation in aqueous solution of the lowest ligand field band of each complex (Table 11) leads to photoaquation of a chloro ligand (eq 5).
Table I. Electronic Spectra of cis- and trans-[Rh(en),XCl]"+
cis- or tr~ns-Rh(en)~XCl"+
hv
Rh(en)2X(H20)("+1)++ C1- (5)
For the trans-Rh(en),XCl"+ complexes, where X = C1 or NH3, the photoaquation reaction is stereoretentive, resulting in trans-Rh(en)zCl( H20)2+and trans-Rh( en),(NH3) (H 2 0 )3+, a Reference 9. The NO; salt, which has 20% trans isomer as a respectively, as the primary photolysis products. The phocontaminant, has E values of 155 and 180 M - I cm-l, respectively. toaquation quantum yield for t r a ~ - R h ( e n ) ~ Cthat l ~ +we report in Table I1 (0.061 mol/einstein a t Air, 405 nm) is virtually as photosubstitution reactions of other d6 amine systems. identical to the value reported by Kutal and Adamsong (0.057 mol/einstein a t A,, 407 nm). Irradiation of the trans-RhExperimental Section (en)2(NH3)C12+complex ion a t 365 nm resulted in the forMaterials. The recrystallized salts of cis- and trans-[Rhmation of tr~ns-Rh(en)~(NH~)(H~O)~+ with a quantum yield .were (en),Clz]N03 and cis- and tr~ns-[Rh(en)~(NH~)Cl](NO~)~ virtually identical to that of the dichloro complex (acl= 0.062 prepared from the previously described procedures.'' The purity of mol/einstein). The trans configuration of both photochemical all of the above compounds was confirmed by electronic spectral' and products discussed above has been confirmed by electronic and by carbon-13 NMR spectr~scopy.'~ The signal-to-noiseratio of the 13Cmagnetic resonance spectroscopy. typical NMR spectra limited nondetectable geometric impurities to
